China Machine Tool Industry Association cnc system jointly organised by the Council of the "second NC system user survey" in the 2002 nationwide " CNC thousands investigation "on the basis again, in 2002, the survey known as the media industry and created a user survey conducted industry precedent, industry leaders called" generous, big, big promotion, "the Investigations so far claimed at professionals Road, the results of the survey are still being used. Then five years later, the NC system is the industry of what is ? Domestic and foreign system of proportional system changed how many ? What enterprises currently occupies in the hearts of users of the weight of more ? Whether the market will re-shuffling ? Through this survey, let us once again to look at cnc system industries. In the whole function of NC machine tools, CNC tool compensation system, the workpiece can outline the size of procedures, the establishment of the implementation of knife-meeting, the NC system automatically calculated, knife-point automatically adjust to the cutter on the trajectory. The direct use of the workpiece size of the processing procedures, tool wear, the replacement of the processing procedures, the use of simple and convenient. Tool Centre in the need to calculate the trajectory of NC system, it is necessary to calculate and parts outline the basic point of nodes and the corresponding tool centre point and the coordinates of nodes. Shown in Figure 1 for the use φ8 end mill processing part of the tool centre trajectory. We can see that the trajectory is the tool parts of the outline of offset, by the outline of parts and tool radius can be derived. Machining centers, CNC milling machine cnc system, including the cutter compensation tool radius compensation, the compensation angle and length of compensation tool compensation.